Photo-/Baso-Chromisms and the Application of a Dual-Addressable Molecular Switch

Graphical Strong as an OX : A dual-addressable molecule (SP- OX-NO 2 ) containing spiropyran (SP) and benzoxazine (OX) was designed by sharing indole in a single molecular system. The bidirectional switching property could be controlled with the stimuli of visible light or base in solution. Further, SP-OX-NO 2 was applied in rewritable paper displaying multicolor with different stimuli including visible light, base and heat. Two typical molecular switches of spiropyran (SP) and benzoxazine (OX) were fused by sharing an indole to achieve a new dual-addressable molecular switch (SP-OX-NO 2 ). Through proper molecular modification with NO 2 , the transformation from merocyanine (MC) to ring-closed SP or ring-closed OX can be controlled separately with visible light or base stimuli in solution, respectively, and these processes are verified by UV-vis and NMR spectroscopy as well as control experiments. The cis -merocyanine ( cis -MC) form is involved in the basochromic process in solution. DFT calculation suggests that the bidirectional switching property of the fused SP-OX molecular switch can be controlled separately, when the OX isomer is more stable than the deprotonated SP isomer. Because of the significant color variations in solution, the simple dual-addressable switch has been further successfully applied to construct a multicolor reversible display on paper.